Apple vacuolar processing enzyme 4 is regulated by cysteine protease inhibitor and modulates fruit disease resistance.

Abstract

Ring rot is a destructive apple disease caused by Botryosphaeria dothidea. The resistance mechanism of apple plants to B. dothidea remains unclear. Here, we show that APPLE VACUOLAR PROCESSING ENZYME 4 (MdVPE4) is involved in resistance to B. dothidea. MdVPE4 silencing reduced fruit disease resistance, whereas its overexpression improved resistance. Gene expression analysis revealed that MdVPE4 influenced the expression of fruit disease resistance-related genes, such as APPLE POLYGALACTURONASE 1 (MdPG1), APPLE POLYGALACTURONASE INHIBITOR PROTEIN 1 (MdPGIP1), APPLE ENDOCHITINASE 1 (MdCHI1), and APPLE THAUMATIN-LIKE PROTEIN 1 (MdTHA1). The expression of the four genes responding to B. dothidea infection decreased in MdVPE4-silenced fruits. Further analysis demonstrated that B. dothidea infection induced MdVPE4 expression and enzyme activation in apple fruits. Moreover, MdVPE4 activity was modulated by apple cysteine proteinase inhibitor 1 (MdCPI1), which also contributed to resistance towards B. dothidea, as revealed by gene overexpression and silencing analysis. MdCPI1 interacted with MdVPE4 and inhibited its activity. However, MdCPI1 expression was decreased by B. dothidea infection. Taken together, our findings indicate that the interaction between MdVPE4 and MdCPI1 plays an important role in modulating fruit disease resistance to B. dothidea.

• Authors: Chaohua Dong, Ronghui Li, Nan Wang, Yingshuang Liu, Yugang Zhang, Suhua Bai
• Journal: Journal of experimental botany (J Exp Bot) Vol. 73 Issue 11 Pg. 3758-3773 (06 02 2022) ISSN: 1460-2431 [Electronic] England
• PMID: 35259265 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: [email protected].

Chemical References

• Cysteine Proteinase Inhibitors
• Polygalacturonase
• Cysteine Endopeptidases
• vacuolar processing enzyme

Topics

• Cysteine Endopeptidases
• Cysteine Proteinase Inhibitors
• Disease Resistance (genetics)
• Fruit (genetics)
• Malus (genetics)
• Plant Diseases (genetics)
• Polygalacturonase